The invention relates to the field of computer systems and memory hardware and, more particularly, to a quad in-line memory module having connectors along two long edges of the module""s circuit board.
Single and dual in-line memory modules (SIMMs and DIMMs respectively) have been developed to provide a convenient means of organizing memory for use in computer systems. SIMMs and DIMMs are compact circuit boards, typically 10 cmxc3x972 cm, with integrated circuit memory chips mounted on one or both sides of the board and electrical connectors along one edge of the board. SIMMs have a row of connectors along one side of one edge of the memory module""s circuit board. DIMMs have connectors along both sides of one edge of the memory module""s circuit board.
FIG. 1 illustrates a computer system 100 in which SIMMs and DIMMs can be used and includes a central processing unit (CPU) 105, system memory 110, a video controller card 115 and display 120, a disk controller card 125 and disk drive 130, a system bus 135 used to communicate data and control signals between the computer system""s 100 different components, a bridge circuit 140 used to couple the system bus 135 to a secondary bus 145, input/output (I/O) control circuitry 150, serial 155 and parallel 160 I/O ports, a keyboard 165, and one or more slots 170 through which additional devices such as an audio card could be connected. Some or all of the elements shown in FIG. 1 may be positioned on the computer system""s 100 main circuit board (motherboard). It will be recognized that the system bus could be a Peripheral Component Interconnect (PCI) bus and the secondary bus 145 could be an expansion bus such as the Industry Standard Architecture (ISA) bus or the Extended Industry Standard Architecture (EISA) bus.
SIMMs and DIMMs are generally mounted with their circuit boards at a right angle to the computer system""s motherboard and populated with dynamic random access memory (DRAM), static random access memory (SRAM), or video random access memory (VRAM) chips. When DRAMs are used the SIMM/DIMM can be used to implement system memory 110. When SRAMs are used the SIMM/DIMM can implement a cache 175 such as found in a disk controller card 125. When VRAMs are used the SIMM/DIMM can implement video memory 180 such as found in a video controller card 115.
A quad in-line memory module composed of a circuit board having top and bottom connectors and a number of memory devices mounted on one or both sides of the circuit board is described. The memory devices may be mounted onto the circuit board via any convenient technique such as surface mount or flip-chip. Additionally, packaged memory devices (e.g., dual in-line packages or DIPs) may also be mounted on the circuit board. Mounted devices may be electrically coupled to the top and bottom edge connectors via conductive paths both on the surface of the circuit board and between the circuit board""s top and bottom surfaces.
A quad in-line memory module in accordance with the invention can provide one or more of the following advantages: (1) increase chip density in a given computer system without requiring additional motherboard area; (2) simplify routing of conductive paths in a memory module for a given number of chips; (3) provide wider data paths to/from a memory module; and (4) reduce line density for a given size of memory module.